chore: move prototype to prototype/, scaffold backend with uv

.gitignore

@@ -5,6 +5,8 @@ __pycache__/
 *.pyc
 .env
 backend/.env
+backend/annotations_cache.sqlite
+backend/.venv/
 .venv/
 
 # contains live API keys — never commit; reference only

backend/.env.example

@@ -0,0 +1 @@
+OPENAI_API_KEY=sk-...   # embeddings only; real key goes in backend/.env (gitignored)

backend/pyproject.toml

@@ -0,0 +1,25 @@
+[project]
+name = "astroparse-api"
+version = "0.1.0"
+requires-python = ">=3.11"
+dependencies = [
+    "fastapi>=0.115",
+    "uvicorn[standard]>=0.32",
+    "sse-starlette>=2.1",
+    "pymupdf4llm>=0.0.17",
+    "datasets>=3.0",
+    "faiss-cpu>=1.8",
+    "openai>=1.50",
+    "httpx>=0.27",
+    "numpy>=1.26",
+    "spacy>=3.8",
+    "en-core-web-sm @ https://github.com/explosion/spacy-models/releases/download/en_core_web_sm-3.8.0/en_core_web_sm-3.8.0-py3-none-any.whl",
+    "python-dotenv>=1.0",
+    "python-multipart>=0.0.9",
+]
+
+[dependency-groups]
+dev = ["pytest>=8", "pytest-asyncio>=0.24", "respx>=0.21"]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"